Refined estimates show BP oil spill released 4.9 million barrels

Newly refined estimates released on Monday by the US government show oil spewed from BP’s Deepwater Horizon spill site at a rate of 53,000 barrels per day immediately preceding the capping stack installation on July 15.

A collaborative effort by the National Incident Command’s Flow Rate Technical Group (FRTG) and a team of Department of Energy (DOE) engineers and scientists have released new estimates showing BP’s leaking well in the Gulf of Mexico was releasing 53,000 barrels of oil per day preceding its closure.

The FRTG, led by United States Geological Survey (USGS) Director Marcia McNutt, and the DOE team, led by Energy Secretary Steven Chu, relied heavily on new pressure readings made available after the new containment cap was put in place on the spewing wellhead.

“The new containment cap and the well integrity testing procedures have provided new data and new opportunities to firm up some of the unknowns and narrow in on a more refined estimate,” said Dr. McNutt. “I appreciate the tireless work of scientists inside and outside of government who are lending their expertise in service to their country and bringing the best science to bear on this effort,” she added on the Deepwater Horizon Response site.

According to latest information available on the site, the scientific teams also estimates approximately 4.9 million barrels of oil spewed from the gushing well during its 87-day direct assault on the global environment.

Results from recent measurements and modeling also show the Macondo well was gushing 62,000 barrels of oil per day at the beginning of the spill, a far cry from the 500 barrels of oil per day initially claimed by BP’s Tony Hayward and retired Coast Guard Admiral Thad Allen.

The decrease in flow from 62,000 bpd to 53,000 bpd was a result of depletion of the hydrocarbon reservoir during the Gulf of Mexico fiasco. The decrease was determined by observations of pressure at shut in and the initial pressure estimates when the well was first drilled.

Monday’s numbers show a startling yet sad trend: figures for total amount of oil released into the Gulf from the spill site has risen steadily and dwarfs all previous estimates.

From the Deepwater Horizon Response site, Monday’s new estimate is based on “a combination of analyses of high resolution videos taken by ROVs, measurements and modeling of reservoir and well properties, acoustic technologies, and measurements of oil collected by the oil production ship together with pressure measurements inside the containment cap.”

The scientific teams held meetings on July 30 and July 31 where they discussed new data points and analyses in helping provide the updated range.

“The revised estimates are part of this Administration’s ongoing commitment to ensuring that we have the most accurate information possible,” said Secretary Chu. “I am grateful to the scientists and engineers who have worked diligently to help us meet that goal.”

Monday’s information ends on the note that government scientists are continuing to analyze available data and, in time, may be able to refine this estimate even more.